open access

https://hdl.handle.net/2115/35512

Importance of water content in formation of porous anodic niobium oxide films in hot phosphate-glycerol electrolyte

英語

glycerol electrolyte

2009-01-01

Elsevier

Electrochimica Acta

54(3)

946-951

Niobium has been anodized at a constant current density to 10 V with a current decay in 0.8 mol dm-3 K2HPO4-glycerol electrolyte containing 0.08 to 0.65 mass% water at 433 K to develop porous anodic oxide films. The film growth rate is markedly increased when the water content is reduced to 0.08 mass%; a 28 μm-thick porous film is developed in this electrolyte by anodizing for 3.6 ks, while the thickness is 4.6 and 2.6 μm in the electrolytes containing 0.16 and 0.65 mass% water respectively. For all the electrolytes, the film thickness changes approximately linearly with the charge passed during anodizing, indicating that chemical dissolution of the developing oxide is negligible. SIMS depth profiling analysis was carried for anodic films formed in electrolyte containing ~0.4 mass% water with and without enrichment of H218O. Findings disclose that water in the electrolyte is a predominant source of oxygen in the anodic oxide films. The anodic films formed in the electrolyte containing 0.65 mass% water are practically free from phosphorus species. Reduction in water content increased the incorporation of phosphorus species.

学術雑誌論文

Accepted Manuscript

0013-4686

AA00633261